Small Bowel Obstruction-Oral Contrast Use?

[anonperson]

This may be an overly simplified question but for suspected small bowel obstruction, is oral contrast necessary or going to add a significant amount of information to the diagnosis versus just using IV contrast?

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[ACSurgeon]

This may be an overly simplified question but for suspected small bowel obstruction, is oral contrast necessary or going to add a significant amount of information to the diagnosis versus just using IV contrast?

This is somewhat surgeon and radiologist dependent, but oral contrast is not necessary for SBO scans.

 

[JayDoc06]

Not needed. Our center, in fact, unless specifically requested, gives water as the only PO contrast. Though I am not a fan, it is perfectly adequate for most things. However, therapeutic gastrograffin after 36-48 hours of decompression is quite useful

 

[SLUser11]

This may be an overly simplified question but for suspected small bowel obstruction, is oral contrast necessary or going to add a significant amount of information to the diagnosis versus just using IV contrast?

Not necessary to dx a SBO. However, water-soluble contrast has a relatively robust body of literature supporting its therapeutic benefit.....I usually do this as a SBFT if the patient isn't progressing well after some time.

Also, not necessary does not mean it's not useful, especially if you don't have the diagnosis hammered out. It's great at helping distinguish a SB loop from an abscess, so if you're looking for an abscess causing an ileus, or numerous other conditions that present with abdominal pain and are on the differential with SBO, then PO contrast is useful.

But, if it's a slam dunk SBO, and the pt is already throwing up bile, I see no reason to add a bunch of volume to the GI tract.

 

[Gadofosveset]

Two additonal points:
- if there's actually an SBO, the PO contrast often becomes diluted and and won't make it to the transition point by the time you start the scan.
- positive oral contrast limits one's ability to evaluate the bowel wall

Like SLUser11 pointed out, the choice depends on pretest probability. If SBO is reasonably high on the differential (or + abdominal radiograph), then don't use PO contrast.
If it's a situation in which there's vague abdominal pain and SBO is thrown out on a differential including both bowel and nonbowel etiologies, then consider PO contrast. A judicious abdominal radiograph may be useful to decide which direction you want to go.

PO contrast isn't used in the emergency department for throughput reasons.

Appendicitis also does not need PO contrast, BTW.

 

[Arcan57]

Two additonal points:
- if there's actually an SBO, the PO contrast often becomes diluted and and won't make it to the transition point by the time you start the scan.
- positive oral contrast limits one's ability to evaluate the bowel wall

Like SLUser11 pointed out, the choice depends on pretest probability. If SBO is reasonably high on the differential (or + abdominal radiograph), then don't use PO contrast.
If it's a situation in which there's vague abdominal pain and SBO is thrown out on a differential including both bowel and nonbowel etiologies, then consider PO contrast. A judicious abdominal radiograph may be useful to decide which direction you want to go.

PO contrast isn't used in the emergency department for throughput reasons.

Appendicitis also does not need PO contrast, BTW.

Our (ED) protocol is no PO for appy, SBO, diverticulitis, pancreatitis, or trauma but we have to tell the radiologist which of those disease entities we are looking for specifically. This basically leaves hunting for bounce back post-op or IBD complications as the main reasons we would give PO contrast to adults, especially since most of our patients carry generous amounts of contrast (intraperitoneal fat) at baseline. And as mentioned above, PO contrast murders throughput especially when combined with a provider with an unwaveringly high pre-test probability across all patient spectrums.

 

[vhawk]

My understand is that all the "PO contrast doesnt add anything" in the ED/Rads literature is based on appendicitis mostly, and explicitly is in the setting of GIVING IV contrast, and the driving factor is increasing throughput in the ED and reducing costs. The problem is that this is then inappropriately extrapolated to other entities, in particular, SBO, and in situations where IV contrast is contraindicated. I wouldnt go as far as to say I disagree that it isnt "necessary" for the diagnosis of SBO....it isnt. Heck, a CT scan probably is barely even "necessary." But thats in a pretty idealized setting. The problem is that in the real world, the ED takes a half assed history, or the hospitalist does, at 2 in the morning, and then orders a non-con scan trying to find any diagnosis that they can foist on another service. Like general surgery!

So, no, if you take a good history, a KUB is probably enough, or an IV contrast scan. But if you are a medicine doc, and you've got someone who is having diarrhea and abd pain, and you are just ordering a scattershot CT scan, PO contrast is crucial. It can convincingly rule out a SBO. Non-con scans routinely are read as "cannot exclude SBO," because sometimes small bowel is just dilated for whatever reason, peristalsis, etc.

This is a bit of a rant, but PO contrast can remove SBO from the DDx when its unclear, and can be used to treat a SBO quite efficaciously in some settings, so if you are in doubt, get it. And dont listen to the ED/rads when they try to tell you the evidence doesnt support it...they are misinterpreting the evidence.

 

[Gadofosveset]

My understand is that all the "PO contrast doesnt add anything" in the ED/Rads literature is based on appendicitis mostly, and explicitly is in the setting of GIVING IV contrast, and the driving factor is increasing throughput in the ED and reducing costs. The problem is that this is then inappropriately extrapolated to other entities, in particular, SBO, and in situations where IV contrast is contraindicated. I wouldnt go as far as to say I disagree that it isnt "necessary" for the diagnosis of SBO....it isnt. Heck, a CT scan probably is barely even "necessary." But thats in a pretty idealized setting. The problem is that in the real world, the ED takes a half assed history, or the hospitalist does, at 2 in the morning, and then orders a non-con scan trying to find any diagnosis that they can foist on another service. Like general surgery!

So, no, if you take a good history, a KUB is probably enough, or an IV contrast scan. But if you are a medicine doc, and you've got someone who is having diarrhea and abd pain, and you are just ordering a scattershot CT scan, PO contrast is crucial. It can convincingly rule out a SBO. Non-con scans routinely are read as "cannot exclude SBO," because sometimes small bowel is just dilated for whatever reason, peristalsis, etc.

This is a bit of a rant, but PO contrast can remove SBO from the DDx when its unclear, and can be used to treat a SBO quite efficaciously in some settings, so if you are in doubt, get it. And dont listen to the ED/rads when they try to tell you the evidence doesnt support it...they are misinterpreting the evidence.

A rad will rarely try to prevent you from getting PO contrast, but the most important reason it's not better for SBO because it throws off one's ability to evaluate subtle attenuation differences in the bowel wall.

Noncon scans really should not be read as "cannot rule out SBO" unless ileus is on the differential... and even then the two are usually differentiable.
It would seem unlikely that PO contrast would make a practical difference in this setting (the PO contrast in a setting of hypomotility takes it sweet time to the cecum, obv).
It won't help much between "low grade" SBO vs ileus.

PO contrast is most helpful for differentiating bowel from non-bowel, esp in the postop abdomen and pelvis. That's when the rad wishes it was on board.

 

[Kahreek]

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